Venous thromboembolism risk in patients with cancer receiving chemotherapy: a real-world analysis

Abstract

The occurrence of malignant disease increases the risk for venous thromboembolism (VTE). Here we evaluate the risk for VTE in a large unselected cohort of patients with cancer receiving chemotherapy.

Methods: The United States IMPACT health care claims database was retrospectively analyzed to identify patients with a range of solid tumors who started chemotherapy from January 2005 through December 2008. International Classification of Diseases, 9th revision, Clinical Modification Codes were used to identify cancer location, presence of VTE 3.5 months and 12 months after starting chemotherapy, and incidence of major bleeding complications. Health care costs were assessed one year before initiation of chemotherapy and one year after initiation of chemotherapy.

Results: The overall incidence of VTE 3.5 months after starting chemotherapy was 7.3% (range 4.6%-11.6% across cancer locations) rising to 13.5% at 12 months (range 9.8%-21.3%). The highest VTE risk was identified in patients with pancreatic, stomach, and lung cancer. Patients in whom VTE developed had a higher risk for major bleeding at 3.5 months and at 12 months (11.0% and 19.8% vs. 3.8% and 9.6%, respectively). Health care costs were significantly higher in patients in whom VTE developed.

Conclusion: Those undergoing chemotherapy as outpatients are at increased risk for VTE and for major bleeding complications. Thromboprophylaxis may be considered for such patients after carefully assessing the risks and benefits of treatment.

Keywords: Cancer; Chemotherapy; Health care costs; Thromboprophylaxis; Venous thromboembolism.

Figure 1.

VTE incidence (95% confidence interval) by cancer site and VTE definition (see text) (A, B, and C) at 3.5 months and 12 months post-index. Data labels indicate point estimates. Abbreviation: VTE, venous thromboembolism.

Figure 2.

Proportions of VTE cases (95% confidence interval) that were DVT only, PE only, or both DVT and PE according to definition A at 3.5 months and 12 months post-index. Abbreviations: DVT, deep-vein thrombosis; PE, pulmonary embolism; VTE, venous thromboembolism.

Figure 3.

Cumulative risk for VTE using definition A in patients with cancer undergoing chemotherapy. Abbreviation: VTE, venous thromboembolism.

Figure 4.

Incidence (95% confidence interval) of major bleeding (using the expanded International Society on Thrombosis and Haemostasis definition) within 12 months after starting chemotherapy (for definitions of VTE A, B, and C) in patients with and without VTE within 3.5 months and 12 months post-index. Data labels indicate point estimates. Abbreviation: VTE, venous thromboembolism.

Figure 5.

One-year pre- and post-index health care costs according to definitions A, B, and C of VTE. (A): One-year pre- and post-index health care costs (mean values [interquartile range]) within 3.5 months post-index in patients with and without VTE, using definitions A, B, and C of VTE. Adjusted annual cost during one-year follow-up post-index according to definitions A, B, and C of VTE. (B): Adjusted annual cost (95% confidence interval) during one-year follow-up post-index in patients with and without VTE, using definitions A, B, and C of VTE (multivariate generalized linear model). Abbreviations: ER, emergency room; Rx, prescription medication; VTE, venous thromboembolism.